1. Field of the Invention
The present invention relates to an image forming system in which an image forming apparatus which forms an image on a sheet, a clear coating apparatus which forms a clear coating image using a clear toner that becomes transparent after fixing, and a bookbinding apparatus are connected.
2. Description of the Related Art
The demand for improved image quality has been increasing in recent years with respect to full-color electrophotographic image forming apparatuses (image forming apparatuses). In addition, as the use of digital cameras is also increasing in popularity, there is a demand for image modes for a high-image quality photographic tone to be realized in electrophotographic image forming apparatuses.
Image forming systems have been proposed in which an image forming apparatus and a clear coating apparatus are connected. In these systems, after outputting an image having a high-quality photographic tone on a sheet, image forming is further performed to form a toner image that becomes transparent after fixing on the sheet (for example, see Japanese Laid-Open Patent Publication (KOKAI) No. 03-13079).
Further, an image forming system is also known in which a bookbinding apparatus that implements a folding mode and a staple mode in which sheets with images formed thereon are folded to make the sheets into a bound book is connected at a stage following an image forming apparatus.
In the conventional image forming system comprising a bookbinding apparatus, there has been a problem that when a sheet on which a toner image has been fixed is folded at the bookbinding apparatus, the toner comes off at the folding position of the sheet. There has also been a problem that, even when the toner that has been fixed at the folding position does not come off at the time of bookbinding, the user opens or closes the bound sheets or contacts a folding position with some object so that the toner at the folding position comes oft.
When the toner that has been fixed at the folding position comes off, the quality of the binding declines, the appearance becomes poor, and the toner that has come off dirties the area around the bound sheets.
Although a counter measure can be considered in which a toner image is not formed at a sheet folding position in order to solve the above problem, when a toner image is not formed at a folding position on the front cover, in particular, the appearance deteriorates.
Further, although forming a clear coating image using the aforementioned clear toner can also be considered as a counter measure to solve the aforementioned problems, when clear toner is used on the entire surface of a sheet it leads to a waste of the clear toner.
Furthermore, although a counter measure may be considered in which the user specifies a position for image formation using clear toner on each individual sheet, this increases the operation burden of the user.
Further, when performing a process in which the center of sheets is stapled and the sheets are then folded, if a clear coat is applied to all the sheets, there are cases in which the thickness of the center of the sheets increases and thus stapling cannot be accurately performed.